Human immunodeficiency virus (HIV) infection is characterized as a systemic immunosuppressive disorder caused by the viral-mediated depletion of CD4 T cells or viral mediated loss of immune competence, which develops into the profound immunodeficiency that underlies the acquired immunodeficiency syndrome (AIDS). AIDS is characterized by various pathological conditions, including immune incompetence, opportunistic infections, neurological dysfunctions, and neoplastic growth.
Many drugs have been approved for the treatment of AIDS. Non-limiting examples of these drugs include nonnucleoside reverse transcriptase inhibitors, such as delavirdine (Rescriptor, Pfizer), Efavirenz (Sustiva, Bristol-Myers Squibb), and evirapine (Viramune, Boehringer Ingelheim); nucleoside reverse transcriptase inhibitors, such as Abacavir (Ziagen or ABC, GlaxoSmithKline), Didanosine (Videx or ddI, Bristol-Myers Squibb), Emtricitabine (Emtriva, Gilead Sciences), Lamivudine (Epivir, GlaxoSmithKline), Stavudine (Zerit, Bristol-Myers Squibb), Tenofovir DF (Viread, Gilead Sciences), Zalcitabine (Hivid, Hoffmnan-La Roche), Zidovudine (Retrovir or AZT, GlaxoSmithKline); protease inhibitors, such as Amprenavir (Agenerase, GlaxoSmithKline and Vertex Pharmaceuticals), Atazanavir (Reyataz, Bristol-Myers Squibb), Fosamprenavir (Lexiva, GlaxoSmithKline and Vertex Pharmaceuticals), Indinavir (Crixivan, Merck), Lopinavir (Kaletra, Abbott Laboratories), Nelfinavir (Viracept or NFV, Agouron Pharmaceuticals), Ritonavir (Norvir or RTV, Abbott Laboratories), Saquinavir (Fortovase, Hoffman-La Roche); and fusion inhibitors, such as Enfuvirtide (Fuzeon, Hoffman-La Roche and Trimeris).
The recommended treatment for HIV is a combination of three or more medications in a regimen called “highly active antiretroviral therapy” or “HAART.” Exemplary HAART regimens include Sustiva+Epivir+(Retrovir, Viread or Zerit), Kaletra+Epivir+(Retrovir or Zerit), Sustiva+Emtriva+(Retrovir or Viread or Zerit), Kaletra+Emtriva+(Retrovir or Zerit), or Reyataz+(Epivir or Emtriva)+(Retrovir or Zerit). Introduction of HAART have led to a dramatic decline in both HIV-related illness and death. Early clinical trials demonstrated a reduction of plasma HIV RNA loads to undetectable levels in the majority of treated individuals. Subsequent studies, however, showed more limited success in achieving and maintaining viral suppression. Many patients experienced immunologic and clinical responses to HAART without sustained suppression of plasma viremia. Therefore, significant challenges still remain in the scientific and clinical battle against HIV and AIDS. In particular, there is a need for new methods that can effectively reduce plasma viremia in HIV-infected individuals.